The present invention relates to an evaporator, in particular for air conditioners in automotive vehicles.
An evaporator for air conditioners is described in DE-OS No. 28 47 525. The evaporator comprises an evaporator block containing a plurality of bifurcated pipes and cooler baffles, and a connector box or tank. A distributor chamber and a collector chamber are integrated in the connector box. The coolant is introduced by means of a coolant injector into the distributor chamber, flows through the U-shaped bifurcated pipes and is dranw off, after entering the collector chamber, through a compressor suction line.
In an evaporator of this type, all of the evaporator pipes consist of bifurcated pipes, each of which extends into the distributor chamber and into the collector chamber. All bifurcated pipes thus form evaporator pipes installed in parallel. In such a configuration, a uniform distribution of the coolant present in two phases with equal phase proportions in all of the parallel evaporator pipes is only adequately possible when the number of parallel evaporator pipes is very low. In view of capacity values customary in automotive vehicles, this means that the evaporator must be very slender and have very long bifurcated pipes. The structural space required for such a design is usually not available. Becasue the plurality of evaporator pipes are supplied by a common injector and distributor chamber, the cooling effect over the block volume is not uniform, since the flow of the coolant is distributed non-uniformly. This non-uniformity leads to a reduction in the performance of the evaporator.
A coolant flow distributor derived from the Venturi tube is described in U.S. Pat. No. 2,803,116. This distributor consists at its inlet side of a Venturi tube and at its outlet side of a plurality of outlet channels, having individual diameters smaller than the narrowest cross section of the Venturi tube. The outlet channels are arranged symmetrically on a conical surface. They form in the center of the Venturi tube a conical point. In known evaporators, distributor pipes are soldered into the outlet channels of the Venturi distributor and these are connected with the evaporator pipes, with the number of outlet channels corresponding to the number of evaporator pipes, consisting of several bifurcated pipes connected in series. In order to obtain the same flow resistance in all of the inlet pipes, they must be individually bent and aligned, resulting in high costs. The soldering of the bifurcated pipes and the functional testing required by it, are also cost intensive processes.